Search Results (213)

Cellulose nanofibers (CNFs) are highly promising nanocarrier materials, boasting excellent drug adsorption and loading potential due to their tunable hydrophilic/lipophilic interfaces. This study is the first to report the successful synthesis of maleic anhydride-modified CNFs (MA-CNFs) via the esterification of CNFs using a solvent-free molten maleic anhydride (MA) system, and it systematically evaluates MACNFs’ dual adsorption performance for water-soluble and lipophilic drugs. A new characteristic peak at 1723 cm⁻¹ in FT-IR confirms the formation of ester bonds, proving the successful grafting of MA onto CNFs. XRD analysis shows that the crystallinity slightly increases from 72.56% to 74.06%, indicating the reaction mainly occurs in the amorphous region. After modification, the material’s hydrophobicity is significantly enhanced (water contact angle: ~63.3° for CNFs vs. ~74.9° for MA-CNFs), and its BET specific surface area rises sharply from 5.03 to 26.29 m²/g. These structural advantages collectively enable MA-CNFs to have adsorption capacities for folic acid (FA, water-soluble) and vitamin E acetate (VEA, lipophilic) that are 1.15 and 2.04 times those of CNFs, respectively. The results demonstrate MA-CNFs are high-performance functional materials fabricated via a green method, with good biocompatibility. Full article

This study investigates the potential of acetylated xylan as a functional component in coatings for biodegradable paper-based food packaging. Acetylated xylan was synthesized in the laboratory via the reaction of native beechwood xylan with acetic anhydride. Multilayer coatings composed of acetylated xylan, chitosan, and zinc oxide nanoparticles (ZnO NPs) were applied to paper substrates as single and double layers (approximately 5 g/m²) to enhance their barrier and antimicrobial properties. The coated papers were evaluated for mechanical properties, resistance to water, oil, and grease, antimicrobial activity against pathogenic bacteria, and biodegradability in soil. The combination of xylan derivatives with chitosan significantly improved surface hydrophobicity (contact angle ~87°) and achieved complete inhibition (100%) of Staphylococcus aureus and Salmonella spp., without compromising biodegradability. Incorporation of ZnO NPs further enhanced both the barrier properties and antimicrobial efficacy, particularly against S. aureus. A high biodegradation rate (~92%) was recorded after 42 days of soil burial. These results demonstrate the suitability of xylan-based multilayer coatings as sustainable alternatives for food packaging applications. Full article

Starch particles (SPs) were extracted from underutilized wild yam (Dioscorea remotiflora) tubers using two methods: (1) acid hydrolysis (AH) alone and (2) acid hydrolysis assisted by ultrasound (AH-US). The SPs were chemically modified through esterification (using acetic anhydride [AA] and lauroyl chloride [LC]) and crosslinking (with citric acid [CA] and sodium hexametaphosphate [SHMP]). They were subsequently characterized by their yield, amylose content, and structural and physical properties. The yield of particles was 17.5–19.7%, and the residual amylose content was 2.8–3.2%. Particle sizes ranged from 0.46 to 0.55 µm, which exhibited mono-modal and bi-modal distributions for AH and AH-US treatments, respectively. Following chemical modification, yield notably increased, especially with substitution by LC (33.6–36.5%) and CA (32.6–38.7%). Modified SPs exhibited bi-modal particle distributions with micro- and nanoparticles and variable peak intensities depending on the chemical compound used. Unmodified SPs displayed irregular morphologies, showing disruptions (AH) or aggregation (AH-US). Chemical substitutions altered morphologies, leading to amorphous surfaces (CA: AH), clustering (LC), or fragmentation into smaller particles (SHMP) under AH-US treatment. FT-IR analysis indicated a decrease in hydroxyl groups’ peak area (A(-OH)), confirming the substitution of these groups in the starch structure. Crosslinking with CA resulted in the highest degree of substitution (AH: 0.43; AH-US: 0.44) and melting enthalpy (ΔH_f: 343.0 J/g for AH-US), revealing stronger interactions between SPs from both methods. These findings demonstrate that the extraction treatment of D. remotiflora SPs and the type of chemical modifier significantly influence the properties of SPs, underscoring their potential applications as natural biocarriers. Full article

Synchronous fluorescence spectra are presented to investigate solute–solvent interactions in liquids. To this end, the spectra of 2-amino-7-nitro-fluorene (ANF) in six different solvents—acetic anhydride, acetone, acetonitrile, benzene, chlorobenzene, and ethyl acetate—are presented. The study also examines ANF’s synchronous fluorescence signals at five temperatures from 25 °C to 5 °C, providing a comprehensive analysis of its fluorescence characteristics in different environments and temperatures. An ANF sample dissolved in benzene at 5 °C produced a synchronous band with the largest intensity and smallest frequency shift. The results show that higher-intensity peaks are obtained at lower temperatures with solvents with a small dipole moment and dielectric constant. This suggest that the best conditions to detect ANF and similar molecules at very low concentrations are with non-polar solvents at low temperatures. Full article

Underutilized starch sources are gaining increasing recognition. However, the inherent functional deficiencies of native starch have limited its application in food industry. To counteract the deficiencies in its native characteristics, starch can be modified by acetylation. Two waxy starches (proso millet and amaranth) and four non-waxy starches (foxtail millet, quinoa, buckwheat, and oat) were modified by acetic anhydride and vinyl acetate, respectively. Degree of substitution of acetylated starches revealed that granule size did not significantly affect acetylation efficiency in starches from different plant origins. Acetylation increased peak and final viscosity of starches, with vinyl acetate exhibiting a more pronounced effect than acetic anhydride. Acetic anhydride decreased K and increased n values of non-waxy starches, showing reduced thickening ability. In contrast, vinyl acetate modification showed opposite trends, suggesting increased viscosity and pseudoplasticity. For non-waxy starches, G′_25°C, G′_0.1Hz, G′_20Hz and gel hardness decreased after acetylation, indicating that acetylation contributed to a less solid and less elastic gel network. The extent of change in vinyl acetate modification was more pronounced than that of acetic anhydride. For waxy starch, vinyl acetate modification decreased tan δ_25°C and increased gel hardness. In summary, acetylation reagent type was the major factor determining the pasting properties of acetylated starch, but the presence or absence of amylose would influence the rheological and gel properties of acetic anhydride and vinyl acetate modified starches. These findings could help unlock the potential applications of acetylated underutilized starches in the food industry. Full article

Combining the properties of organic and inorganic components with high surface areas and large pore volumes opens up countless possibilities for designing materials tailored to a wide range of advanced applications. As the majority of mesoporous hybrid materials are siliceous, the development of cost-effective synthetic approaches to produce water-stable hybrids with controlled porosity and functionality remains essential. Herein, we describe an original strategy for the synthesis of bridged mesoporous titania–bisphosphonate hybrids based on a one-step, template-free, non-hydrolytic sol–gel process. The reaction between Ti(OiPr)₄ and several flexible or rigid bisphosphonate esters, in the presence of acetic anhydride (Ac₂O) leads to the formation of TiO₂ anatase nanorods interconnected by fully condensed bisphosphonate groups. The general method that we depict is quantitative and low cost. All materials are mesoporous with very high specific surface areas (up to 520 m²·g⁻¹) and pore volumes (up to 0.93 cm³·g⁻¹). Full article

Synthetic plastic impacts the environment due to its slow degradation and the generation of microplastics, driving the development of bioplastics. This study evaluated the use of bagasse fiber combined with corn and potato starch to improve the physical and mechanical properties of bioplastics. Five bioplastic mixtures (Am1 to Am5) were prepared with corn starch, glycerin, acetic acid, maleic anhydride, and agave bagasse. Am1 was prepared without bagasse, and the others were prepared with different amounts of bagasse (0, 10, 30, 50, and 70 g). Bioplastics made from potato starch (Ap1 to Ap5) were also produced under the same conditions and were assessed using the thermogravimetric (TGA) and scanning electron microscopy (SEM) tests. Analysis of variance showed significant differences (p < 0.001) in the moisture, Young’s modulus, and stress of the bioplastics. The corn-based bioplastics exhibited lower moisture values (7.26% and 5.51%) compared to the potato-based ones (9.68% to 8.89%). Young’s modulus and stress increased in the corn-based (Am5 = 4.59 MPa) and potato-based (Ap5 = 3.53 MPa) bioplastics with higher amounts of bagasse. Furthermore, TGA and SEM revealed the surface morphology and the effects of processing, and based on their results, it was found that agave bagasse improved the mechanical and thermal properties of bioplastics, especially corn-based ones, suggesting its potential as a material with a lower environmental impact. Full article

Introduction. Many pharmacological properties of dipyridamole (DIP) are associated with its ability to inhibit phosphodiesterases (PDEs). Actually, DIP has interesting properties like antiviral for influenza, SARS-2 COVID-19, and herpesviruses. Our research aimed to design and synthesize the dynamic combinatorial DIP derivatives with more pronounced inhibiting properties in relation to PDE and to carry out the HPLC analysis of the resulting combinatorial derivatives of DIP. This study is aimed at investigating the effect of the dynamic derivative of dipyridamole (DDD) on intestinal dysbiosis syndrome in mice caused by streptomycin against the background of cyclophosphamide-induced cellular immunodeficiency. Materials and methods. For the synthesis of a dynamic combinatorial derivative of dipyridamole, we used a molecular dynamic method for drug design and combinatorial acylation of dipyridamole by succinic and acetic anhydride in different molar ranges of acylation agents. Combinatorial derivatives were analyzed using gradient HPLC with a UV detector. Also, derivatives established the inhibition ability for phosphodiesterase by the spectrophotometric method. Also, we used an in vivo mouse model with immunodeficiency caused by cyclophosphamide for pharmacological study. Results and discussion. Molecular modeling suggests that 18 different dipyridamole derivatives can self-assemble into a stable supramolecular structure with lower total energy. Specific combinatorial molar ratios of the synthesis components were necessary to create a new supramolecular compound with enhanced pharmacological properties. The inhibition of phosphodiesterase in such a dynamic combinatorial derivative already appeared at a concentration of 0.05 μM. In mice with colitis caused by streptomycin treatment, the administration of DDD per os resulted in an antidiarrheal effect and prevention of the animals’ weight loss. Given the cyclophosphamide-induced immunosuppression and streptomycin-associated diarrhea, immunity was completely restored only under the action of DDD. Conclusions. The most effective dipyridamole derivative for phosphodiesterase inhibition was formed only if the number of different derivatives in solution was maximum and consisted of all 18 molecules. With other quantities of modifiers, there was no qualitative change in the inhibitory activity of the combinatorial mixture against phosphodiesterase. According to all parameters, DDD has been proven to be more effective than the pure dipyridamole reference product. Full article

Hair care products that have oxidative hair dye ingredients have been widely used to permanently change hair color for the characteristic and younger appearance of people and/or their companion animals. In the European Union and the Republic of Korea, these ingredients have been carefully used or prohibited for cosmetic products according to their genotoxic potential. There is a growing demand for reliable quantification methods to monitor oxidative hair dye ingredients in hair care products. However, accurately quantifying oxidative dyes in cosmetic samples is challenging due to their high reactivity and chemical instability under both basic and ambient conditions. For this reason, for the quantification methods, elaborate sample preparation procedures should be accompanied by chemical derivatization to avoid chemical reactions between hair dye ingredients, before instrumental analysis. Therefore, this study utilized a gas chromatography–mass spectrometry (GC-MS) method combined with in situ chemical derivatization to quantify 26 oxidative hair dye ingredients in hair care products. In situ derivatization using acetic anhydride provided the characteristic [M-CH₂CO]⁺ ions at m/z (M-42), produced by the loss of a ketene from the hair dye ingredient derivatives. These characteristic ions can be used to establish a selective ion monitoring (SIM) mode of GC-MS. The established method was successfully applied to hair dye products (n = 13) and hair coloring shampoos (n = 12). Most products contained unintended hair dye ingredients including catechol without labeling. It was cautiously speculated that these unintended hair dye ingredients might be caused by biodegradation due to various enzymes in natural product extracts. This study presents a reliable GC-MS method with in situ derivatization to quantify 26 oxidative hair dye ingredients in hair care products, addressing challenges related to their chemical instability. This method is crucial for public health and regulatory compliance. Full article

Brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA) and dibromoneopentyl glycol (DBNPG), are present in both saturated and unsaturated polyester resins (UPRs). Given their toxicity, it is imperative to assess the content of this group of chemicals to ensure product safety and environmental sustainability, considering the paucity in the literature of analytical methods to evaluate them, particularly in solid matrices as UPRs. This study aimed to develop a fully automated gas chromatographic analysis of these BFRs, utilizing a flame ionization detector (FID), with prior derivatization of TBBPA and DBNPG with acetic anhydride. A chemometric evaluation was conducted for the derivatization step to enhance the yield of the procedure. The optimized method met the desired requirements for specificity, accuracy, and sensitivity, showing limits of detection (LOD) and quantitation (LOQ), respectively, of 1.1 µg/mL and 3.3 µg/mL for DBNPG and 3.6 µg/mL and 10.8 µg/mL for TBBPA. Other conventional detectors, i.e., an Electron Capture Detector (ECD) and a Mass Spectrometer (MS), were tested. The ECD showed a higher sensitivity than the FID and MS; however, its linearity proved to be more limited, making it unsuitable for higher concentration scenarios. The MS detector yielded results comparable with those of the FID, yet the latter is a cheaper and more sensitive alternative. Full article

Purification and characterization of milk oligosaccharides is a challenging process due to the complexity of the constituent oligosaccharides, which behave differently under various chemical treatment procedures and often lose their structural properties in the process. Rathi cow’s milk is widely used in the Rajasthan region of India for its nutritional and medicinal benefits. Here, we aim to present an optimized method for the purification and analysis of oligosaccharides present in Rathi cow milk. Contrary to the freeze transport methods used earlier, we treated the collected milk with ethanol for preservation, followed by microfiltration, lyophilization, and fractionation on silica gel (60–120 mesh size) column chromatography (CC) coupled with chloroform/methanol-mediated gradient elution. Fractions 31–45 (1.78 g), 71–80 (470 mg), and 106–120 (498 mg) from CC-1 and fractions 26–49 (1.14 g) from CC-2 were analysed for sugar content via the phenol–sulfuric acid method. Fraction homogeneity was confirmed using high-performance liquid chromatography. Isolated analytes were treated with acetic anhydride/pyridine (1:1, v/v) to form less polar oligosaccharide derivatives, which could then be easily visualized and semi-quantitated using partition chromatography (thin later and paper) with chloroform/methanol. Structural identities of the purified oligosaccharides were determined using a combination of mass spectrometry and NMR (¹H, ¹³C, HSQC, TOCSY, COSY, HMBC) techniques. Our results clearly demonstrate that the ethanol-based preservation, transport, and purification of oligosaccharides is a simple and robust method for the analysis of Rathi cow’s milk oligosaccharides. Furthermore, using the acetylation, purified oligosaccharides allow for rapid analysis on thin-layer chromatography, which is quite cost effective compared with other analytical methods. Full article

Chemical modification is an environmentally friendly option for wood preservation. It can improve the performance and dimensional stability of wood, increase its resistance to deterioration and ensure safe disposal once out of service. Wood acetylation is the esterification of accessible hydroxyl groups in the cell wall with acetic anhydride, which reduces the hygroscopicity of wood. Acetic acid is obtained as a byproduct of the reaction. The aim of this work is to determine the best reaction conditions for the acetylation of Pinus taeda wood with acetic anhydride. The experimental design used was a 2² factorial design with three repetitions in the midpoints. Reaction temperature and reaction time were taken as independent variables, each at two levels. The weight gain percentage of wood (WPG) and its chemical changes were used as response variables. The durability of the wood acetylated under the best treatment conditions as determined before was tested against decay fungi (Gloeophyllum separium and Trametes versicolor). The results show that temperature was the most impactful variable on the WPG results. Higher WPGs were obtained at temperatures above 100 °C. The acetylated wood was highly resistant to fungal attack, with very low mass losses. Full article

Many designs of industrial reactors stem from designs from the 1960s–1970s. For a wide range of reactions, these designs lead to suboptimal reaction configurations due to limitations in heat- or mass-transfer. Process intensification has come up with a different approach, resulting in micro- and mini-reactors being safer and more cost-effective on a full industrial scale. However, based on the experience in the suboptimal reactor designs, the reaction rates of these reactions seem too low for full-scale reactions in a mini reactor. We suggest a test for the reaction rate based on a generalized model in combination with a specific type of mini-reactor: the rotor–stator spinning disc reactor. The generalized model is based on existing models on residence time distribution in such reactors. It does not need to be tailor-fitted for a specific rotor–stator spinning disc reactor that is used for the test, as is the case with current models. In this article, we show that our simplifications induce a difference in outcome in reaction rate of less than 10% with the existing models. Experiments with the well-studied chemical reaction of the hydrolysis of acetic anhydride show that the reaction rates calculated based on this scan fall within the range of reported data from the literature. Full article

This study aims to enhance the mechanical properties of hot-waxed wood by incorporating microcrystalline cellulose (MCC), thereby addressing the issue of inadequate surface durability. We investigated the effects of varying mass fractions (0%, 5%, 10%, 15%) of MCC on multiple surface properties of hot-waxed wood modified with natural wax and maleic anhydride-ethyl acetate copolymer-grafted Fischer-Tropsch wax. These properties encompass adhesion, hardness, abrasion resistance, impact resistance, surface roughness, gloss, and hydrophobicity. To gain deeper insights into the reinforcing role of MCC, analytical techniques such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) were employed to comprehensively characterize the chemical structure, crystalline structure, and surface morphology of the samples. The results reveal that, upon the addition of 5% MCC, the hot-waxed wood treated with modified Fischer-Tropsch wax demonstrates a 41% increase in surface adhesive strength, an improvement in hardness from 2H to 3H, a reduction in surface impact resistance from grade 5 to grade 2, and a 72% decrease in wear mass. Additionally, it exhibits enhanced surface hydrophobicity and thermal stability, while preserving its decorative appearance. These findings endorse the use of MCC in hot-waxed wood, offering significant potential in fields like wooden architecture, indoor wooden decorative panels, and furniture. Full article